纳米线中声学极化子及其自陷转变

发布时间：2019-05-09 04:32

【摘要】：低维材料与人们的生活息息相关，因此对低维材料的深入研究受到了各个领域研究人员的重视。由于纳米材料其特有的性能，使得纳米材料在纳米电子器件的连接、光导纤维、集成电路、太阳能电池等各个领域有着至关重要的作用。电子的自陷可以让人们更加深入的了解纳米线的特殊性能，对提高人们的生活水平有着重要的意义。这篇论文研究的是柱型纳米线中电子与声学声子的相互作用以及这种相互作用可能导致的极化子自陷转变。首先采用Huybrechts变分法，运用柱型纳米线中电子—声学声子相互作用哈密顿量，对其进行两次么正变换，计算出了纳米线中声学极化子的基态能量，便于讨论柱型纳米线中声学极化子的自陷问题。研究结果表明，判断柱型纳米线声学极化子能否自陷的判别标准q0的近似值比一维系统中声学极化子自陷标准大，但是比三维系统声学极化子自陷标准小。因此纳米线中声学极化子的自陷难易程度介于一维情况和三维情况中间，并且半径越小，纳米线声学极化子的自陷转变越容易发生。运用文中计算得到的纳米线中声学极化子自陷的判断标准，，在理论上判断了GaN、AlN等材料中声学极化子的自陷。结果表明：GaN和AlN中的电子均有可能在纳米线结构中自陷。这对今后进一步研究纳米材料有一定的借鉴意义。
[Abstract]:Low-dimensional materials are closely related to people's lives, so the in-depth study of low-dimensional materials has been paid attention to by researchers in various fields. Due to the unique properties of nano-materials, nano-materials play an important role in the connection of nano-electronic devices, optical fiber, integrated circuit, solar cells and so on. The self-trapping of electrons can make people understand the special properties of nanowires more deeply, and it is of great significance to improve people's living standards. This paper deals with the electron-acoustic phonon interaction in columnar nanowires and the possible polaron self-trapping transition caused by this interaction. Firstly, the ground state energy of the acoustic polaron in the nanowires is calculated by using the Huybrechts variation method and the electron-acoustic phonon interaction Hamilton in the cylindrical nanowires, and the unitary transformation is carried out twice to calculate the ground state energy of the acoustic polaron in the nanowires. It is convenient to discuss the self-trapping problem of acoustic polaron in cylindrical nanowires. The results show that the approximate value of criterion Q0 is larger than that of acoustic polaron self-trapping in one-dimensional system, but smaller than that of acoustic polaron self-trapping in three-dimensional system. Therefore, the degree of self-trapping of acoustic polaron in nanowires is between one-dimensional and three-dimensional cases, and the smaller the radius is, the more likely the self-trapping transition of acoustic polaron in nanowires will occur. Based on the criterion of acoustic polaron self-trapping in nanowires calculated in this paper, the self-trapping of acoustic polaron in GaN,AlN and other materials is theoretically judged. The results show that the electrons in GaN and AlN may trap themselves in nanowire structure. This can be used for reference in the further study of nano-materials in the future.
【学位授予单位】：山西师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O469

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